The phase-cut dimming mode has some advantages. It is convenient for users to install and wire the circuit. Further, it is easy to convert the lighting circuit wiring in the old buildings into a lighting solution with a dimming function. Hence, the phase-cut dimming mode is more and more widely used. However, the input voltage range of the current phase-cut dimming power supply is narrow. For example, the input voltage range of the phase-cut dimming power supply which is suitable for the regions of China, Europe, Australia etc. is within 170-265V, and the input voltage range of the phase-cut dimming power supply which is suitable for the regions of North America, Japan etc. is within 90-130V. Therefore, there is no phase-cut dimming power supply having an input range within 90-305V, which is suitable for most of electrical networks in the whole world. Besides, some available phase-cut dimming power supplies still use power regulation to realize phase-cut dimming. The phase-cut power supplies in this mode have some problems. For example, the load power is limited. Further, it cannot adjust various LED lights with different colors at the same time and the input voltage range is narrow. There are also some available phase-cut dimming power supplies using a PWM control. Even though various LED lights with different colors can be adjusted in this mode, this mode can only be used in a phase-cut power supply with a narrow input voltage range, since it collects the voltage amplitude of the input voltage to generate a control signal.
As described above, there are deficiencies, including limited load power, failure to adjust various LED lights at the same time, narrow input voltage range, etc., in the existing phase-cut dimming power supplies.